"After more than 50 years since the invention of the laser, nonlinear optics has provided a viable solution to the generation of coherent light in arbitrary spectral regions from the UV to mid-IR. In the ultrafast regime, the exploitation of novel multistep nonlinear frequency conversion concepts based on parametric down-conversion and... mehr
The potential of functionalized nanoparticles and their outstanding properties is not fully exploited yet. There are a lack of methods to integrate these properties into materials and products. Pulsed laser ablation in liquids is a particular technique that allows the production of high-purity nanoparticles and their functionalization with biomolecules... mehr
Hyperspectral imaging has gained importance in biomedical, chemical, industrial, aerospace and defense applications. In this article we see how ultimate performance, LWIR hyperspectral imaging technology is developed towards new capabilities for high-end sectors.
Photoluminescence imaging of large-area silicon wafers was demonstrated at the University of New South Wales, Sydney, in 2005, and since then, the technique has proven to be a versatile, contactless method for measuring a range of important material and device parameters. It offers an unprecedented combination of short measurement time and high... mehr
The increasing power of digital image processing makes more and more application areas accessible. Industry, in particular, demands ever increasing camera resolutions and frame rates with high information content. High information content typically means image colour and a high "image quality" in general, but also the additional gain that can... mehr
Todays hyperspectral image processing technology is primarily confined to laboratory use. This could change rapidly once practical solutions for fast, compact, user-friendly and low-cost hyperspectral cameras become available. Such cameras will open broad industrial applications, such as optical sorting in food safety, waste recycling, and medical... mehr
Whenever the assured properties of technical and decorative surfaces cannot be ensured by the manufacturing process alone, determining surface quality through visual inspection is one of the most commonly used methods in industrial production. The following article describes a method for the surface inspection of 3D parts, by which both the efficiency... mehr
Biomedical research demands technology that enables capture and analysis of molecular and microscopic structures, as well as dynamic 3-dimensional processes without disturbing or influencing the sample. Numerous fluorescence microscopy techniques permit optical sectioning, and thereby provide detailed insight into samples without the need to mechanically... mehr
LEDs are more efficient than light bulbs, transforming roughly 30% of supplied electric power into light, yet 70 % of this energy is cast off as heat. This lost heat needs to be dissipated because high temperatures affect the semiconductor's properties and, ultimately, its lifespan. The following article takes a closer look at the thermal aspects... mehr
Gratings with periods smaller than visible wavelengths exhibit colourising effects in the zeroth diffraction order when its profile is designed so that electromagnetic resonances are excited on the grating. These resonances have a spectral selective influence to the light spectrum and allow colour filtering of even unpolarised white light. Apart... mehr
Highly efficient anti-reflective coatings minimize disruptive reflection losses for optical components, such as precision optical lenses or ophthalmic lenses. Surface measurements for coatings, which are taken in quality assurance steps by means of scanning spectral photometers, are either destructive or else they cannot be taken at any user-defined... mehr
Both the equipment and the measurement parameters play important roles in achieving reliable in-line colour measurement results. This article highlights several issues to remember during system implementation in production environments. In particular, the use of spectrometers and colorimeters for in-line measurement is discussed, as along with... mehr
Today's optical lenses are produced either through conventional surface machining, or through various replication procedures. Below we compare these manufacturing methods and detail the benefits of classic miniature optics manufacturing, including the realisation of stable production series.
Precision glass moulding enables the cost-effective production of extremely precise and complex optical components from glass. In order to communicate both the capabilities and the possible uses of the technology, "design recommendations" have been developed. These present the complex technological interdependencies in a comprehensive yet practical... mehr
CNC grinding and polishing are well established procedures in manufacturing optics. Lately, plasma- and ion-beam based techniques are more frequently used as alternatives to CNC methods. This is due to the higher accuracy requirements of optical systems with improved precision. Polishing error correction, using residence time controlled ion beam... mehr
With improved variants of ion beam sputtering and spectral broadband monitoring, particularly stable optical layer systems for high-performance and short-pulse lasers can be manufactured. Gradient layer coatings can now be achieved with previously unrealised stability parameters.
Deposition technology has evolved tremendously since the first single layer optical interference coating was presented more than 70 years ago. Today, methods involving evaporation deposition, IBS, and APRS are amongst the preferred technologies for thin-film production. This article discusses the differences between various coating technologies... mehr
High-power diode laser quality was once described by only total output power and electro-optical efficiency. Today's applications require better characterisation of diode lasers by their brightness, which is the "usable" output power.
Industrial expectations on the performance of lasers for today's high-tech diagnostic instruments continue to grow stronger and stronger. Typically compact, continuous wave (CW), diode pumped solid state lasers (DPSSLs) are integrated into such systems, often replacing legacy gas lasers such as Argon ion, or lamp pumped systems. The lasers may... mehr
We describe four experimentally simple, accurate, and reliable methods for measuring both simple and very complex ultrashort light pulses. Although each method comprises only a few optical elements, they permit the measurement of extremely complex pulses with time-bandwidth products greater than 65,000. Two techniques measure the complete spatio-temporal... mehr
Most lenses cause geometric distortions. This is especially the case with wide-angle lenses, and this may be termed as the "fish-eye effect". It is notable that the geometrical distortion does not affect the general quality of the picture, only its geometry. Within certain limits this distortion can therefore be arithmetically corrected. In this... mehr
Future indoor light distribution of living and office spaces will improve significantly when large-area micromirror arrays are used in conventional double-glazed windows. In contrast to macroscopic solutions, such micromirror array-based solutions are nearly invisible, weatherproof, and maintenance free. Custom application across large areas requires... mehr
Designers of beam manipulation and imaging systems often encounter the need to fold their optical layout into a more compact form, or to redirect light to the next component. In either case, the choice inevitably arises between mirrors, or alternatively, prisms. Solutions may often be found either way, but making the best selection up-front could... mehr